【作者】 张帆；

【导师】 范春菊；

【作者基本信息】 上海交通大学 ， 电气工程， 2017， 硕士

【摘要】 随着我国经济的飞速发展,电力工业作为国民经济的命脉,也得到了飞速的发展,全国各地的电力网络规模不断扩大。随着电力事业的不断发展与建设,电力系统规模的不断扩大,输电线路的空中走廊越发紧张。同塔多回输电线路在我国已经大规模应用与输配电网络中。同塔多回线之间的互感,使得各回线路存在耦合,传统的适用于单回线的保护判据是否能适用于同塔多回线都是亟待解决的问题,给线路继电保护带来新的挑战。本文旨在对双回线、四回线和跨电压等级四回线的实际应用情况以及故障分析和继电保护的研究基础上,研究了跨电压等级四回线的继电保护方案。分析了跨电压等级四回线的负序电流特征,根据故障时的负序电流特征,提出了基于负序电流分量的两种横差保护方案,即适合于同电压等级双回线的小横差保护和适合于不同电压等级线路的跨线故障的大横差保护,且分别给出了横差保护的整定方法,综合两种横差保护的动作信号提出了基于横差保护动作特性的四回线故障选线方案。针对跨电压等级四回线接地故障的特点,提出了一种新的接地距离保护方案。在分析单回线接地距离保护接线方式的基础上,研究了跨电压等级四回线接地距离保护中各回线之间的零序互感对零序阻抗补偿系数的影响,提出了适合于跨电压等级的四回线的接地距离保护接线方式,即考虑不同电压等级的四回线的耦合系数的零序补偿系数方法。采用该接线方式时,当四回线发生接地故障时,保护安装处的测量阻抗与保护安装处到故障点的距离成正比。针对跨电压等级四回线接地距离保护抗过渡电阻能力的问题,考虑应用零序电继电器来增强其抗过渡电阻能力。同时,采用负序突变量方向元件来判别故障方向,该方向元件不受负荷阻抗的影响且具有很强的方向性。两者的结合可以提高跨电压等级输电线路的接地短路保护的抗过渡电阻的能力,又不失方向性。更多还原

【Abstract】 With the rapid development of China’s economy,the power industry as the lifeblood of the national economy,has also been rapid developed.Power network expands throughout the whole country.With the continuous development and construction of power grids,the aerial corridors of transmission lines become more and more tense.Multi-circuit transmission line on the same tower in China has been large-scale applied in the transmission and distribution network.Coupling and mutual inductance among the transmission lines brings new challenges to traditional protection.How the characteristics of protection criterion changes,are the protection scheme still applicable are problems to be solved urgently.Based on the actual application of the four-circuit lines of the double-circuit line,quadruple-circuit lines of different voltage grades,fault analysis and relay protection research status relay protection schemes of quadruple-circuit lines of different voltage grades are proposed.Considering the characteristics of negative sequence current of the quadruple-circuit lines of different voltage grades,a new transverse differential protection and line selection method based on the action signal of the transverse differential protection is proposed.Negative sequence currents of each line are calculated and analyzed,when a fault occurs,negative-component based transverse differential protection approach is proposed.The setting value of the protection and the line selection method is also proposed.A new grounding distance protection scheme is proposed for the quadruple-circuit lines of different voltage grades.Considering the influence of zero-sequence mutual inductance among the transmission lines,when cross line grounding fault occurred in quadruple-circuit lines of different voltage grades,the deviation of measured impedance could lead to malfunction or disoperation of the relay.Based on the traditional approach of the zero-sequence mutual inductance,a new zero sequence current compensation coefficient for quadruple-circuit lines of different voltage grades applied to the ground distance protection of quadruple-circuit lines of different voltage grades considering the zero sequence coupling of different voltage is proposed.When the cross line ground fault occurs,the impedance measurements will be proportional to the distance between the relay location and the fault location.Considering the shortcomings of the quadruple-circuit lines of different voltage grades grounding distance protection scheme and the weak anti-transition resistance capability,the zero-sequence reactance relay is applied to the quadruple-circuit lines of different voltage grades grounding distance protection to enhance its anti-transition resistance performance.At the same time,the direction of the fault is identified by using the negative-sequence abrupt directional element,which is not influenced by the load impedance and has strong directivity.The combination of the directional element and the zero-sequence reactance relay improves the resistance of the transition resistance while the directionality is kept.更多还原